Copyright 2007 John Wiley & Sons, Inc. Chapter 51 Network Computing

Copyright 2007 John Wiley & Sons, Inc. Chapter 52 Chapter Outline  5.1 Types of Networks  5.2 Internet  5.3 The World Wide Web  5.4 Network Applications  5.5 E-Learning and Distance Learning  5.6 Telecommuting

Copyright 2007 John Wiley & Sons, Inc. Chapter 53 Learning Objectives  Describe the two major types of networks.  Differentiate among the Internet, the World Wide Web, intranets and extranets.  Describe the four major network applications.  Describe groupware capabilities.  Differentiate between e-learning and distance learning.  Understand the advantages and disadvantages of telecommuting for both employers and employees.

Copyright 2007 John Wiley & Sons, Inc. Chapter Types of Networks  Computer network is a system that connects computers via communications media so that data can be transmitted among them.  Local area network (LAN) connects two or more devices in a limited geographical region.

Copyright 2007 John Wiley & Sons, Inc. Chapter 55 Local Area Network (LAN)  LAN consists of the following components:  LAN file server is a repository of various software and data files for the network.  Nodes are the client machines on the LAN.  Wired or wireless communication media that connects the devices.

Copyright 2007 John Wiley & Sons, Inc. Chapter 56 Local Area Network (Continued)  LAN network interface card (NIC) is a special adapter that links an individual device to the communication medium and specifies: The rate of data tramsmission; The size of the message units; Addressing information attached to each message; The network topology.  Network operating system (NOS) manages the server and routes and manages communications on the network.

Copyright 2007 John Wiley & Sons, Inc. Chapter 57 Network Topologies  Star, all network nodes connect to a single computer, typically the file server.  Bus, all network nodes connect to the bus, which is a single communications channel, such as twisted pair, coaxial calbe, or fiber optic cable.  Ring, network nodes are connected to adjacent nodes to form a closed loop.

Copyright 2007 John Wiley & Sons, Inc. Chapter 58  Let see fig. 5.1 and table 5.1

Copyright 2007 John Wiley & Sons, Inc. Chapter 59 Wide Area Network (WAN)  Wide area networks (WANs) are networks that cover large geographic areas. WANs typically connect multiple LANs. WANs have large capacity and combine multiple channels (fiber optic, satellite, microwave, etc.). WANs provided by common carriers, such as telephone companies (Sprint, AT&T, etc.).  Value-added network (VAN) are private, data- only networks managed by outside third-parties that provide these networks to multiple organizations.

Copyright 2007 John Wiley & Sons, Inc. Chapter 510 Enterprise Networking  Enterprise network is an organization’s interconnected network of multiple LANs and also can include multiple WANs.  Backbone networks are corporate high- speed central networks to which multiple smaller networks such as LANs called embedded LANs and smaller WANs connect.

Copyright 2007 John Wiley & Sons, Inc. Chapter 511  Let see fig. 5.2

Copyright 2007 John Wiley & Sons, Inc. Chapter The Internet  Internet (“the Net”) is a global WAN that connects approximately 1 million internal organizational computer networks in more that 200 countries on all continents.  ARPANET An experimental project started by the U.S. Department of Defense (DoD) in 1969 To share data, exchange messages, transfer files.

Copyright 2007 John Wiley & Sons, Inc. Chapter 513 Internet Technologies  Intranet is a network designed to serve the internal informational needs of a single organization.  Extranet connects part of the intranets of different organizations and allows for secure communications among business partners over the Internet using virtual private networks.

Copyright 2007 John Wiley & Sons, Inc. Chapter 514 Internet Technologies (Continued)  Virtual private network (VPNs) are private communications networks that use the internet for transmission.  Tunneling encrypts the data packet to be sent, and places it inside another packet; which provides confidentiality, authentication and integrity of the message.

Copyright 2007 John Wiley & Sons, Inc. Chapter 515  Let see fig 5.3 and fig. 5.4

Copyright 2007 John Wiley & Sons, Inc. Chapter 516 Darknets  Darknets are private networks that run on the Internet but are open only to users who belong to the network.  Three major uses: Freedom of speech where censorship exists; Corporate security to protect sensitive data; Copyright infringement - file-sharing software.

Copyright 2007 John Wiley & Sons, Inc. Chapter 517 Operations of the Internet  Internet Protocol (IP) the set of rules used to send and receive packets from one machine to another over the Internet.  Packet switching is a transmission technology that breaks up blocks of text into small, fixed bundles of data called packets.

Copyright 2007 John Wiley & Sons, Inc. Chapter 518 Assessing the Internet  Connecting via an Online Service by opening an account with an Internet Service Provider. Internet Service Provider (ISP) is a company that offers Internet connections for a fee. Examples are AOL, Comcast, Verizon. Network access points (NAPs) are an exchange point for Internet traffic. NAPs are key components of the Internet backbone.

Copyright 2007 John Wiley & Sons, Inc. Chapter 519 Assessing the Internet (Continued)  Connecting via Other Means by making assess to the Internet cheaper, faster and easier. Internet Kiosks are terminals located in public places like libraries and airports for people who do not have computers. Internet assess from cell phones, pagers and even connecting via satellite.

Copyright 2007 John Wiley & Sons, Inc. Chapter 520 Addresses on the Internet  Each computer on the Internet has an assigned address, called an IP address. (i.e )  Domain Name System (DNS) the naming system for IP addresses of companies.  Domain names consist of multiple parts, separated by dots, which are read from right to left. (i.e.

Copyright 2007 John Wiley & Sons, Inc. Chapter 521 The Future of the Internet  Internet2 develops and deploys advanced network applications such as remote medical diagnosis, digital libraries, distance education, onine simulation and virtual libraries  Next Generation Internet (NGI) government sponsored initiative aimed at creating an Internet that is fast, always on, everywhere, natural, intelligent, easy and trusted.  vBNS is a high-speed network designed to support the academic Internet2 and the NGI initiatives.

Copyright 2007 John Wiley & Sons, Inc. Chapter The World Wide Web  World Wide Web (the Web, WWW, W3) is a system of universally accepted standards for storing, retrieving, formatting and displaying information via a client/server architecture and a graphical user interface.  Home page is a text and graphical screen display that welcomes the user and explains the organization that has established the page.  Web site is all the pages of the organization.

Copyright 2007 John Wiley & Sons, Inc. Chapter 523 WWW (continued)  Webmaster the person in charge of the organization’s Web site.  Uniform resource locator (URL) points to an address of a specific resource on the Web.  Hypertext transport protocol (HTTP) is the communications standard used to transport pages across the Web portion of the Internet.

Copyright 2007 John Wiley & Sons, Inc. Chapter 524 WWW (Continued)  Browsers provide a graphical front end that enable users to point-and-click their way across the Web, a process called surfing. Provide a uniform interface regardless of operating system. Leading browsers are Microsoft’s Internet Explorer, Mozilla’s Firefox, Netscape Navigator.

Copyright 2007 John Wiley & Sons, Inc. Chapter Network Applications  Network applications support businesses and other types of organizations in all types of functions including those in the following major categories:  Discovery  Communications  Collaboration  Web services

Copyright 2007 John Wiley & Sons, Inc. Chapter 526 Discovery  Discovery allows users to browse and search data sources, in all topic areas, on the Web.  Search engine is a computer program that searches for specific information by key words and reports the result.  Directory is a hierarchically organized collection of links to Web pages.

Copyright 2007 John Wiley & Sons, Inc. Chapter 527 Discovery (Continued)  Metasearch engines search several engines at once and integrate the findings of the various search engines to answer queries posted by users.  Software agents are computer programs that carry out a set of routine computer tasks on behalf of the user and in so doing employ some sort of knowledge of the user’s goals.

Copyright 2007 John Wiley & Sons, Inc. Chapter 528 Software Agents  Web-browsing-assisting agents offer the use of a tour of the Internet.  FAQ agents make it easy to find answers on the Internet.  Intelligent-indexing agents (also called Web robots and spiders) carry out massive autonomous searches of the Web for a user.

Copyright 2007 John Wiley & Sons, Inc. Chapter 529 Discovery (Continued)  Toolbars is a horizontal row or vertical column of selectable image icons or buttons.  Discovery of material in foreign languages use an automatic translation of Web pages to find information in different languages. babelfish.altavista.com babelfish.altavista.com

Copyright 2007 John Wiley & Sons, Inc. Chapter 530 Portals  Portal is a Web-based, personalized gateway to information and knowledge that provides relevant information from different IT systems and the Internet using advanced search and indexing techniques.  Commercial (public) portals offer content for diverse communities and are most popular portals on the Internet

Copyright 2007 John Wiley & Sons, Inc. Chapter 531  Let see fig 5.10

Copyright 2007 John Wiley & Sons, Inc. Chapter 532 Portals (Continued)  Affinity portals support communities such as a hobby group or a political party.  Mobile portals are accessible from mobile devices.  Corporate portals offer a personalized single point of access through a Web browser  Industrywide portals for entire industries.

Copyright 2007 John Wiley & Sons, Inc. Chapter 533 Communication  Electronic mail ( ) is the largest-volume application running on the Internet.  Web-based call centers (customer call center) are services that provide effective personalize customer contact as an imporant part of Web-based customer support.  Electronic chat room is a virtual meeting place where groups of regulars come to “gab”.

Copyright 2007 John Wiley & Sons, Inc. Chapter 534 Voice Communication  Internet telephony (VoIP) voice-over IP digitizes your analog voice signals, sections them into packets, and sends them over the Internet.  Weblog is a personal Web site, open to the public, where the creator expresses feelings or opinions.  Wiki is a Web site on which anyone can post material and make changes quickly, without using difficult commands.

Copyright 2007 John Wiley & Sons, Inc. Chapter 535 Collaboration  Collaboration refers to efforts of two or more entities (individuals, teams, groups or organizations) who work together to accomplish certain tasks.  Work group refers specifically to two or more individuals who act together to perform some task.  Virtual group (team) is when group members are in different locations.

Copyright 2007 John Wiley & Sons, Inc. Chapter 536 Collaboration (Continued)  Virtual collaboration is the use of digital technologies that enable organizations or individuals to collaboratively plan, design, develop, manage and research products, services and innovative applications.  Workflow technologies facilitate the movement of information as it flows through the sequence of steps that make up an organization’s work procedures. Includes workflow management and workflow systems.

Copyright 2007 John Wiley & Sons, Inc. Chapter 537 Groupware  Groupware refers to software products that support groups of people who share a common task or goal and who collaborate to accomplish it.  Teleconferencing is the use of electronic communication that allows two or mmore people at different locations to hold a simultaneous conference.

Copyright 2007 John Wiley & Sons, Inc. Chapter 538 Groupware (Continued)  Videoconference is when participants in one location can see participants at other locations and share data, voice, pictures, graphics and animation by electronic means.  Web conferencing is videoconferencing conducted over the Internet.  Real-time collaboration tools support synchronous communication of graphical and text-based information i.e. computer-based whiteboards.

Copyright 2007 John Wiley & Sons, Inc. Chapter 539 Web Services  Web services are applications, delivered over the Internet, that users can select and combine through almost any device (from personal computer to mobile phones). It is able to expose and describe itself to other applications, tell what services it does. It can be located by other applications via an online directory. It can be invoked by the originating application by using standard protocols.

Copyright 2007 John Wiley & Sons, Inc. Chapter 540 E-Learning and Distance Learning  E-Learning refers to learning supported by the Web.  Virtual classrooms in which all coursework is done on-line and classes do not meet face- to-face.  Distance learning (DL) refers to any learning situation in which teachers and students do not meet face-to-face.

Copyright 2007 John Wiley & Sons, Inc. Chapter 541 Benefits of E-Learning  Self-paced and self-initiated learning has been shown to increase content retention.  Online materials offer the opportunity to deliver very current content of high quality and consistent.  Students have the flexibility of learning from any place at any time at their own pace.  Learning time generally is shorter, and more people can be trained due to faster training time.  Training cost can be reduced, and savings can be made on facility space as well.

Copyright 2007 John Wiley & Sons, Inc. Chapter 542 Drawbacks of E-Learning  Instructors may need training to be able to teach electronically.  The purchase of additional multimedia equipment may be necessary.  Students must be computer literate and may miss the face-to-face interaction with instructors.  There are issue with assessing students’ work, as instructors really do not know who completed assignments.

Copyright 2007 John Wiley & Sons, Inc. Chapter 543 E-Learning (Continued)  Advanced e-learning support environments, such as Blackboard and WebCT, allow instructors to take advantage of new content and delivery technologies.  Virtual universities are online universities from which students take classes from home or at an off-site location, via the Internet.

Copyright 2007 John Wiley & Sons, Inc. Chapter 544  THE END OF SESSION 9 AND 10